1. Field of the Invention
The present invention relates to a battery equalizer for cars, and more particularly, to a battery equalizer for cars whose electrical characteristic is improved.
2. Discussion of the Related Art
In general, cars (such as a bus and a truck) have a 24V power source system. A 24V battery module in which a 28V alternator and two 12V batteries are seriously connected to each other is used.
The battery equalizer for cars is mounted in the 24V battery module to sustain the voltage of the two serially connected 12V batteries to be always the same and to supply a power source to a 12V electrical load.
Here, when a 12V power source is used for the 12V batteries without the battery equalizer, in the two 12V batteries, a lower end battery is discharged and an upper end battery is charged. Therefore, balance of the voltage of the two batteries is broken so that the lower end battery is over-discharged and the upper end battery is over-charged.
As a result, it is not possible for the lower end battery to use the power source without the battery equalizer.
The battery equalizer converts the power of a 24V input to control an output to be half of the input and to be connected to the lower end battery. When the 12V load is smaller than the capacity of the battery equalizer in a state where the 24V battery module is connected to the battery equalizer, the voltage of the two batteries is sustained to be always the same.
In a conventional art, the ground of the battery equalizer is connected to a battery ground through a wire.
However, in the conventional battery equalizer for cars, when the ground of the battery equalizer is connected to the battery ground through the long wire, the internal ground of the battery equalizer becomes unstable due to the impedance of the wire, the erroneous operation of a product is caused by internal and external noises, and electrical characteristic test standards are not satisfied.